Schematic representation of linear dichroism observed in KL x-ray emission. Coupling between the spin-orbit interaction and the molecular field, oriented along the chemical bond, leads to different spin-orbit ratios as a function of the angle between the incoming and outgoing photons polarization.

Using the polarimeter capabilities of our x-ray spectrometer, we have recently measured the polarization of x-ray photons emitted in a molecular core-to-core transition accompanying resonant inelastic x-ray scattering (RIXS). In this study, we have measured KL emission spectra corresponding to the filling of a 1s core hole by a 2p core electron following core-hole excitation Cl(1s)^-1→(11a₁)¹ in CF₃Cl, and Cl(1s)^-1→(6σ)¹ in HCl (hν=2823,5 eV in both cases). We have observed a linear dichroism in polarized x-ray-emission spectra. In a combined experimental and theoretical effort, we showed this effect is sensitive to coupling between the molecular field (MF) and spin-orbit interactions and interpreted the observed dichroism in terms of population differences in the 2p_x;y;z inner-shell orbitals. Polarized RIXS offers a unique opportunity to determine spin-orbit-component populations, providing a new probe of MF effects on electronic structure.

¹UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement, F-75005 Paris, France
²CNRS, UMR 7614, Laboratoire de Chimie Physique Matière et Rayonnement, F-75005 Paris, France
³Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA
⁴Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

Work performed on ALS Beamline 9.3.1

Citation: R. Guillemin, S. Carniato, W.C. Stolte, L. Journel, R. Taïeb, D.W. Lindle, and M. Simon, "Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular Spin-Orbit States,"Phys. Rev. Letters 101, 133003 (2008).